This invention concerns a new process for the purification of hemin, a novel hemin derivative usable in the process, as well as a process for its preparation.
Hemin is used in medicine i.e., as a water soluble complex compound with basic amino acids, for example L-arginine, for the preparation of pharmaceutical preparations, especially injection preparations, which may be used for the treatment of various types of anemia and especially for the treatment of porphyrism, (see FI-patent 68970).
Hemin may be prepared by splitting hemoglobin from blood using different methods. Thus as the starting material, for example, whole blood or red cell concentrates may be used. According to a modification of a method described by Labbe et al. in the publication Biochem., Biophys. Acta 1957, 26, 437, hemin may be isolated from human blood (red cell concentrate) with a mixture of acetone and acetic acid. In this treatment the cell material and the proteins are separated as a solid substance, which is removed by centrifugation. The centrifuged solution contains the hemin. By evaporating the major part of the solvents the hemin is made to crystallize at room temperature.
A problem has, however, been the preparation of hemin in a form sufficiently pure for medicinal use. According to literature (Fischer, Hans: Organic Synthesis, Collective, Vol. 442-443 (1955) hemin may be crystallized from chloroform pyridine glacial acetic acid. Crystallization from chloroform pyridine-glacial acetic acid does not purify hemin very effectively. In the DE-publication 36 08 091 Al is disclosed a process for the separation and purification of hemin by crystallizing the same from an acid aqueous solution in the presence of tensides. A disadvantage of this purification process is the insufficient degree of purity of the hemin obtained, which is approximately 98% by weight.